Electrolytes are used for many types of electrochemical devices, some of these are batteries, electrochromic (EC) devices, sensors, actuators, fuel cells and capacitors and solar cells to name a few. Such electrolytes may be solid or liquid. Electrolytes allow the mobility of the ions while restricting electronic conductivity. The electrolytes of this invention comprise nanoparticles. One role of the nanoparticles is to selectively restrict the movement of larger ions as compared to smaller ions. The nanoparticles also reinforce the electrolyte in order to provide superior mechanical properties to the solid electrolytes while providing pathways for ionic movement. To meet the above goals the nanoparticles used in this invention are disc shaped, i.e., their thickness is smaller as compared to their other two dimensions. In discs, the thickness has nano dimensions of about less than 100 nm and preferably below 50 nm and most preferably below 10 nm. The width and length may be nanosized or larger.
The disc shaped nanoparticles may be used in several applications. In EC devices the use of these can lead to decreased thickness of electrolyte layers, ease of fabrication of solid devices and enhanced device performance. The ion mobility in the electrolyte can be selectively decreased for larger ions which could lead to decreased power requirements and hence allow fabrication of low power consumption displays. Another area could be decreased electrolyte thickness in a variety of EC devices and glazing, e.g. in automotive mirrors, thin electrolytes reduce the environmental impact due to reduction in chemicals in electrolytes, which also result in reduced material cost. In electrochemical actuators, reinforcement by these particles may impart high modulus and high elongation characteristics to the electrolytes or the redox electrodes so that the force exerted by reinforced polymers may be increased for equivalent power consumption. Disc shaped nanoparticles may also be used for forming encapsulation layers (or barrier layers) to protect EC or other electrochemical devices from the environment.
Nanowires (or nanorods) of conducting and semiconducting materials may also be used to make composites for fabricating redox electrodes for electrochemical devices with superior properties. In many devices where thick electrodes are used (about 1 μm or thicker), the electronic conductivity may be poor, and the use of such nanowires can overcome the conductivity limitations. In nanowires, the average linear cross-section (e.g. diameter) has nanodimensions of about less than 100 nm and preferably below 50 nm and most preferably below 30 nm.
An object of this invention is to disclose use of nanoparticles in electrochemical devices such as electrochromic devices, batteries, photochromic devices, actuators, etc. to enhance their properties.
Another objective of this invention is to disclose specifics of nanoparticles and their use in electrolytes, electrodes, barrier layers and processing methods to achieve devices with enhanced properties.